To hear either of Haydn's two towering oratorios in any given season is a singular bit of luck. To get both back to back within days of each other is sheer bounty. Sunday night the Oratorio Society of Washington will perform "The Creation." Last night the Choral Arts Society, reversing the order of things, did "The Seasons" at the Kennedy Center. This is Haydn's last major composition, save for two final masses. And it has everything going for it: infinite variety, choral writing of the utmost refinement, three solo vocal parts of operatic breadth and an orchestral accompaniment that sums up the ripe wisdom of a master with all 104 symphonies behind him.

Washington is blessed with first-class choral ensembles. The Choral Arts Society is first among equals and may just possibly be the greatest unpaid (not unprofessional) choral group in the country. Under their gifted conductor, Norman Scribner, they didn't let a single Haydn subtlety escape them. The women were delightfully tipsy in the drinking chorus, the men pompously jovial in the "tallyho!" hunting chorus.

Of the three soloists, Jan Opalach, the young baritone, is not yet ripe enough for this music, though his voice is lyrical and pleasing. Gene Tucker was the dependable though rather bland tenor. Soprano Linda Zoghby stood out. Since singing the same part here nine years ago with Antal Dorati and the National Symphony, her voice and artistry have grown immeasurably. She is now the Mozart/Haydn soprano of one's dreams.

If you missed "The Seasons," you can still be present at "The Creation."